iOS Question iOS soft keyboard character and BACKSPACE, ENTER detection

Private Sub TextView1_TextChanged (OldText As String, NewText As String)
    If NewText = "~" Then Return
    If NewText = "" Then
        Log("backspace")
    Else
        Dim c As String = NewText.SubString(NewText.Length - 1)
        Log($"new char: ${c}, codepoint: ${Asc(c)}"$)
    End If
    Dim field As B4XView = Sender
    Sleep(0)
    field.Text = "~"
End Sub